I've done up to 6 hours a pair, and even 10 hours over the course of a week when I was JROTC. Here's basically how it works:
Clean any dirt and dust off of the shoe, you want it to be as clean as possible.
Put a nice gob of spit in a can of kiwi polish or a splash of water to get the polish nice and gooey.
Rub the spit/water into the polish until you have a nice paste going on.
Take that paste and apply a nice thick layer to the shoe. This layer should be thick and hazy and look nasty. That's okay. The polish should be beginning to dry (works best if you heat up the polish a little bit) by the time you finish that coat.
Take a lighter or put the shoe over a stove, and run the flame along the shot so that the polish and the leather heat up. The pores in the leather will open and absorb the polish and you'll see while it's heating up, the polish liquifies and looks realy glossy
after hte whole shoe looks like that, take it away from the flame and let it cool, then buff it away with a soft cloth. That first coat should already look decent, but for that Patent Leather mirror finish, it takes a lot more.
After you finish that first coat, you take your cloth and apply small bits of polish to the shoe rubbing in dime size circles until the polish disappears within the shine. Gradually, the polish will become deeper and shinier, giving a better look than patent leather. Basically you just keep doing this over and over and over and over until the shoe looks the way you want it to, and that takes time.
There are several other methods, and I've tried most of them, but this seems to have been the best way to get a real deep and mirror shine.
That's how these boots here were done: http://upload.wikimedia.org/wikipedi...rill_boots.JPG
It takes time, patience, and a lot of boredom to polish your shoes to that level. You don't really know how shiny they can get until you sit there for hours on end buffing and buffing away at the polish. That's what we were taught in JROTC and i apply the same methods to my dress shoes.
Note: The Guard at Buckingham Palace actually take blowtorches and sponges full of polish to their boots to really get a ridiculous glass-like gloss.